This invention concerns urea and urea condensate reacted with sewer sludge for use as fertilizer, to produce resins, as odor controlling and as fire retardant agent. The invention also concerns the preparation and use of nitrogen containing compound produced by reacting urea or urea condensates with the compounds in sewer sludge. The nitrogen containing compounds produced by reacting urea or urea condensates with sewer sludge and/or its composition is useful in the reduction of odor in the process of dehydrating sewer sludge for use as a fertilizer, also useful in production of resins such as formaldehyde-urea condensate-sewer sludge resins, as a flame retardant to stop house fires, grass and forest fires, to produce flame retarded water based plastic, flame retarded plastics, flame retardant polyurethane foam, etc, and fire retardant flammable organic materials by incorporating in or by spraying on the outside of materials.
Urea in the form of a solid compound has been used as a flame retardant agent in polyurethane foams as outline in U.S. Pat. No. 4,385,131 (Fracalossi, et al.). Many patents use solid urea condensates, urea phosphates, urea borates and urea derivative as the flame retardant agent. Dried sewer sludge is used as a fertilizer but has a very low nitrogen content. The reaction of urea with sewer sludge, the use of urea to react with the sulfur containing compounds in sewer sludge and the use of aqueous or powdered nitrogen containing compound of urea condensates to reacted with sewer sludge as odor suppressant, as fertilizer with a high nitrogen content, for adjusting the pH of the sewer sludge and as the fire retardant compound are novel. When solid urea is used in sufficient amounts, as the flame retardant compound in the production of flame retardant organic products, such as polyurethane products it leaves a slummy or soapy feel to the outer surface of the urethane products, which is very undesirable. The urea migrates out and the product becomes less fire retardant. When the powdered or aqueous nitrogen containing compound urea and urea condensate reacted with sewer sludge are utilized, it reacts with the polyisocyanate and becomes a part of the product. There is no slimy or soapy feel to this foam Aqueous or solid urea condensate reaction products of sewer sludge when used as a fertilizer is very environmentally safe product, also safe to use to put out grass and forest fire and to flame retard organic materials. The aqueous or solid urea condensate reaction products of sewer sludge has both a rapid acting and a long acting nitrogen component. The ammonium salts and urea are rapid acting and the urea condensate and it""s salts are long acting fertilizer with a slow release of nitrogen. When used for fire fighting the aqueous urea condensate reaction produced with sewer sludge may contain coloring agents such as iron oxide, thickening agents, gelling agents, corrosive inhibitors, bactericide agents, surfactant and wetting agents. The urea reacted with sewer sludge increases the nitrogen content in the sewer sludge fertilizer. The sewer sludge reacted with urea will react with aldehydes to produce aldehyde-urea-urea condensate sewer sludge resins.
What is lacking and what is needed are useful, safe and inexpensive products produced by reacting urea with sewer sludge. What is additionally lacking are compositions having aqueous or powdered nitrogen containing compound, such as urea or urea condensate reacted with sewer sludge, employed therein. What is additionally lacking is a method to reduce the odor from heating wet sewer sludge. What is additionally lacking is a method to produce resins utilizing sewer sludge.
The wet sewer sludge cake contains many compounds both organic and inorganic. The urea and/or urea condensate will react with many of the compounds that are found in the sewer sludge such as sulfur oxyacids, urea, amino compounds, carbohydrates, hemicellulose, fatty acids, glycerine, amides, etc. Much of the sewer sludge is non-reacted fillers.
In one aspect, the invention comprises the aqueous or powdered nitrogen containing compound, urea-urea condensate-sewer sludge compositions products produced by reacting urea or urea condensates with sewer sludge. Another aspect of the invention is a process to prepare the aqueous or solid nitrogen containing compounds produced by reacting urea or urea condensate with sewer sludge and/or a composition.
Another aspect of this invention is the process to prepare an aqueous or solid nitrogen containing compounds, urea-urea condensate-sewer sludge compositions produced by reacting urea and/or urea condensate with sewer sludge and/or a composition by reacting and/or mixing:
(A) urea and/or urea condensate, in the amount of 10 to 200 parts by weight;
(B) sewer sludge, in the amount of 100 to 200 parts by dry weight;
(C) carbonization auxiliaries, in the amount of 0 to 300 parts by weight;
(D) metal containing compound that will accelerate the carbonization process, in the amount of 0 to 30 parts by weight;
(E) filler, in the amount of 0 to 300 parts by weight;
(F) water, in the amount of 0 to 500 parts by weight.
Another aspect of this invention is to apply the flame retardant compound of this invention in or on a more flammable organic material (Component H). The flame retardant compounds, aqueous or sold nitrogen containing compound, urea and urea condensate reacted with sewer sludge and/or it""s composition, may be used.
Another aspect of this invention is to utilize the aqueous nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or the aqueous nitrogen containing compounds, urea and urea condensate reaction products with sewer sludge composition to fight fires such as grass fires, forest fires, house fires, furniture fires, etc. In fighting grass fires a solution of aqueous urea-urea condensate-sewer sludge and/or aqueous nitrogen containing compound of urea, urea condensate reacted with sewer sludge composition, with or without, surfactant, to produce bubbles, may be sprayed directly on the flames or may be sprayed in front of the flames thereby wetting the organic materials in front of the fire. The aqueous urea and urea condensate reacted with sewer sludge and/or it""s composition, even after drying, and for several day afterwards, will prevent the coated organic materials such as grass, leaves and bushes from catching on fire when exposed to flames.
Another aspect of this invention is to utilized urea or urea condensate to react with the sulfur compounds in the sewer sludge to reduced the odor produced by heating the sewer sludge. The urea and urea condensate also reacts with other compounds in the sewer sludge to produce fertilizer with an increase in the nitrogen content of the bio-fertilizer. The non-reacted urea may be used as a fertilizer.
Another aspect of this invention is to utilized the urea-urea condensate-sewer sludge composition to produce resins. This composition will react with aldehydes, polycarboxyl acids and/or anhydrides and polyepoxy compounds to produce resins.
Urea in any suitable form such as granules, beads, powder or an aqueous solution may be used in this invention. The urea may be first heated to form a urea condensate then used in this invention. The urea and/or urea condensate is used in the amount of 10 to 100parts by weight.
Any suitable sewer sludge may be used in this invention. It is preferred that the sewer sludge be in the form of a wet compressed solid mass. The sewer outflow is treated with coagulating compounds and the solids are coagulated, then the excess water is filtered off. The remaining solids are compressed into a wet solid mass known as a cake. The compressed sewer sludge contains many different compounds such as cellulose, carbohydrates, nitrogen containing compounds such as urea, proteins, amides, amino compounds and others, minerals, organic and inorganic salts, sulfur compounds and other compounds. The sewer sludge, based on it""s dry weight, is used in the amount of 100 to 200 parts by weight, based on the weight of the urea.
Any suitable carbonization auxiliaries may be utilized in this invention. Suitable carbonization auxiliaries are compounds that in the presence of fire assist the formation of a carbonization foam or char, such as, additives that produce acidic components in the pyrolysis mixture, such as phosphorus acids, boric acids or sulfuric acids. These acidic components are compounds such, for example, acids or salts, or their derivatives of sulfur, boron and phosphorus, such as, boron-phosphates, silicon-phosphorus compounds, phosphates, and polyphosphates of ammonia, amines, polyamines, amino compounds, thioureas and alkyanolamines, but boric acid and its salts and their derivatives, organic phosphorus compounds and their salts, halogenated organic phosphorus compounds, their salts and their derivatives, sulfuric acids, their salts and their derivatives such as ammonium sulfate, urea sulfate, etc., may also be used for this purpose. The commonly known fertilizer which contains phosphorus or sulfur are inexpensive carbonization auxiliaries that can be used with the aqueous urea-urea condensate-sewer sludge, especially in fire fighting and fire prevention and are preferred. The carbonization auxiliaries and other flame retardant agents may be used in quantities of 0 to 300 parts by weight. The carbonization auxiliaries and other flame retardant agents are not a necessary component but when used is used in an amount of 5 to 200 part by weight. The ammonium phosphates may also act as a corrosive inhibitor.
The nitrogen containing salts of phosphorus acids are the preferred carbonization compounds, such as amino phosphate, amine and polyamine phosphates, amino salts of organic phosphorus compounds and amino condensation salt of inorganic and organic phosphorus compounds. The condensation salt of phosphorus compounds are produced by contacting urea condensates such as, biuret, cyanuric acid and cyamelide or other amino compounds with a phosphorus containing compound that will react with an amino compound, under conditions sufficient to prepare an amino salts of a phosphorus containing compound. Suitable inorganic phosphorus compounds include, but not limited to, phosphoric acid, pyrophosphoric acid, triphosphoric acid, metaphosphoric acid, phosphorous acid, hydrophosphorous acid, phosphinic acid, phosphinous acid, phosphine oxide, phosphorus trihalides, phosphorus oxyhalides, phosphorus oxide, and their salts, amino phosphates, amine phosphates, mono-metal hydrogen phosphates, ammonium dihydrogen phosphate, ammonium phosphate, bromated phosphates, alkali metal dihydrogen phosphate, and halogenated phosphate-phosphite and their halides and acids. organic phosphorus compounds include, but not limited to, alkyl, cyclic, aryl and alkyl-aryl phosphorus compounds, such as, alkylchlorophosphines, alkyl phosphines, alkyl phosphites, dialkyl hydrogen phosphites, dialkyl alkyl phosphonates, trialkyl phosphites, organic acid phosphates, organic diphosphonate esters, aryl phosphites, aryl hydrogen phosphates, halogenated phosphonates esters, biuret phosphate, cyanuric phosphate, cyamelide phosphate, and urea, biuret, cyanuric acid and cyamelide borates and mixtures thereof.
Any suitable metal-containing compound that will accelerate carbonization effect used in this invention increases the amount of carbonization residue after combustion, thereby enhancing the flame retardant effect and may be used in this invention. These compounds include, but not limited to, alkaline earth metal borates such as magnesium borate, calcium magnesium borate and the like, manganese borate, zinc borate, metal oxides of titanium oxide, tin oxide, nickel oxide, zinc oxide and the like, ferrocene, dimethylglyoxime copper, acetyl-acetonatocooper, hydroxyquinoline nickel and the like, zinc thiocarbamate compounds such as zinc dimethylthio-carbamate , zinc di-n-butyldithiocarbamate and the like, mercaptobenzothiazole zinc compounds such as mercaptobenzothiazole zinc and the like, salicyadehyde zinc compounds such as salicylaldehyde zinc and the like, metal hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium magnesium hydroxide, zirconium hydroxide and the like and mixtures thereof. The most preferable compounds are selected from zinc oxide, zinc thiocarbamates, the mercaptobenzothiazole zinc compounds the salicyaldehyde zinc compounds, zinc borate and the alkaline earth metal borates. The are utilized in the amount of 0 to 30 parts by weight. These metal containing carbonization accelerators are not necessary components but when used it is used in the amount of 1 to 30 parts by weight.
Any suitable filler may be used in this invention. The fillers that may be utilized in the fertilizer and/or flame retardant mixture may be insoluble in the reaction mixtures. They may be inorganic substances, such as, alkali metal compounds, alkaline earth metal compounds, alkali metal silicates, alkaline earth metal silicates, oxides or hydroxides, metal silicates, silica, metals oxides, carbonates, sulfates, phosphates or borates, glass beads or hollow glass beads. Hydrated aluminum oxide is preferred in the flame retardant composition. Lime is preferred in the bio-fertilizer. They may be organic substances, such as, amino compounds, such as urea, melamine, dicyandiamide, urea condensates, urea-amino condensates, partially hydrolyzed urea condensates and other amino derivatives or their formaldehyde resins, amino phosphates, amino salts of organic phosphates, phenol-aldehyde resin powder, ammonium sulfates, urea sulfates, biuret sulfate, nitrogen containing sulfates, powdered coke, graphite, graphite compounds, Portland cement, lignin, lignin sulfate, lignin sulfite and mixtures thereof. The organic halide flame retardant compounds may also be added as fillers. The filler may be used in the amount of 0 to 300 parts by weight. Fillers are not a necessary component, but useful, and if used is used in the amount of 5 to 300 parts by weight.
Any suitable surfactant that will assist in the production of bubbles or used as a wetting agent may be used in this invention, such as soaps, detergents and silicon surfactants, such as water-soluble polyester siloxanes,. Any surface active agent that will assist in the formation of foam or as a wetting agent such as cationic, anionic, non-ionic and amphoteric surfactants may be used in this invention. The surfactant may be used in the amount of 0 to 30 parts by weight. The surfactant is not a necessary component except when bubbles and wetting agents are desired, then it is used in the amount of 1 to 30 parts by weight.
Water may be added to the reactants or may be added to the nitrogen containing compound, urea-urea condensate-sewer sludge or its composition to produce aqueous solutions. Water may be added in any suitable amount but usually in the amount of 0 to 500 parts by weight based on the weight of the urea.
Any suitable organic material which is more flammable than the aqueous or solid nitrogen containing compound urea and/or it""s composition may be used in this invention. Any suitable plastic resin composition or mixtures thereof and any suitable natural organic material maybe used in this invention and mixtures thereof. These materials may be in the form of a solid, cellular suspension, emulsion or solution but the plastic are preferable to be in the form of or a suspension, emulsion, solution or as a liquid monomer. Suitable plastic resin include, but not limited to, vinyl dienes, vinyl-diene copolymers, polyesters, polyester resins, phenoplasts, aminoplasts, polyepoxy resins, polyurethanes, furans, polyamides, polyimides, polycarbonates, homopolymers of such olefins as ethylene, propylene, and butylene; block copolymers, consisting of optional combination of these olefins; polymers of vinyl compounds such as vinyl chloride, acrylonitrile, methyl acrylates, vinyl acetates and styrene; copolymers of the foregoing olefins with vinyl monomers, copolymers and terpolymers of the foregoing olefins, with diene compounds; polyesters such as polyethylene terephthalate, polyester resins; polyamides such as nylon; polycarbonates, polyoxymethylene, silicones, polyethers, thioplasts, polytetrafluoroethylene, polysulfones, vinyldienes, poly(vinyl acet compounds, cyclic unsaturated compounds, urethane-epoxy resins, polyimides, urethane silicates, cellulose nitrate rayon, regenerated cellulose film cellulose acetate, cellulose esters, cellulose ethers, cyanoethyl cellulose, chlorinated rubber and mixtures thereof.
Suitable natural products include but not limited to grass, weeds, leaves, wood, cellulose, lignin-cellulose, paper, cotton, wool, linen, dammars, copols, other natural resins, rosins, lignin, lignin sulfate, lignin sulfite, natural rubber, natural proteins, e.g., soya bean protein, silk, glues, gelatin, etc.; modified cellulose and mixtures thereof. Natural organic material and plastics may be mixed together. The nitrogen containing compound urea condensate salt of sulfur oxyacid and/or the nitrogen containing compound urea condensate salt of sulfur oxyacid composition, maybe utilized in the amount of 3-200 percent, percentage based on the weight of the more flammable organic material.
Any suitable polyisocyanate may be used in this invention organic polyisocyanates are preferred. The commercial available ones are preferred such as tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, polymethylene polyphenyl isocyanate, diphenylmethane 4,4xe2x80x2-diisocyanate, 3-methlydiphenyl-methane-4,4xe2x80x2-diisocyanate, m- and p-phenylenediisocyanante, polyphenylpolymethylene isocyaxiates obtained by phosgenation, commercially known as xe2x80x9ccrude MDIxe2x80x9d, modified polyisacyanates and mixtures thereof. Suitable organic polyisocyanates are exemplified by the organic diisocyanate which are compounds of the general formula
Oxe2x95x90Cxe2x95x90Nxe2x80x94Rxe2x80x94Nxe2x95x90Cxe2x95x90O
wherein R is a divalent organic radical such as an alkylene, aralkylene or arylene radical. Such radical may contain 2 to 20 carbon atoms. Any suitable compound with active hydrogens may be reacted with the polyisocyanates to produce polyurethane products. The preferred compound with active hydrogens are polyols. Polyurethane catalyst, blowing agents, surfactants, foam stabilizers, dyestuff, plasticizers, propellant, desiccant and fillers may also be used. Polyisocyanate which has the formula
Q(NCO)m
in which m represent a number from 2 to 4 and Q represents an aliphatic hydrocarbon radical having 2 to 18 C atoms, a cycloaliphatic hydrocarbon radical having 4 to 15 C atoms, an aromatic hydrocarbon radical having 6 to 15 C atoms, or araliphatic hydrocarbon radical having 8 to 15 C atoms, in the amount of 25 to 100 parts by weight, and an organic compounds with 1 or more active hydrogens which will react with an isocyanate, in the amount of 25 to 100 parts by weight, containing a urethane catalyst, in the amount of 0.25 to 10 parts by weight, a plasticizer, propellants and a silicone surfactant, in the amount of 0.5 to 5 parts by weight, may be used as the flammable organic material. Any suitable polyepoxy compounds may be used in this invention such as ally glycidyl ether, tert-butyl glycidyl, and the like.
In general, the urea and/or aqueous urea are usually produced by reacting ammonia and carbon dioxide in an aqueous medium while under heat and pressure. This aqueous urea may be utilized in this invention or the urea can be crystalized by removing some of the water. The solid urea may then be added to water to form an aqueous solution of urea which usually contains less than 50% urea. The concentrated aqueous urea may be heated to about its boiling point to produce urea condensates which are soluble in water or the urea heated to or above the melting point to produce a urea condensate such as biuret, cyanuric acid and cyamelide or a partially hydrolyzed urea condensate. Ammonia is produced by heating urea to produce the urea condensate.
Any suitable amount of the aqueous or solid nitrogen containing compound, urea and urea condensate reacted with sewer sludge and/or it""s composition, which may include carbonization auxiliaries, metal containing compounds that accelerated carbonization, heat reflecting substances, surfactant and fillers may be used and added to sewer sludge, biofertilizer and/or flame retardant materials. Preferably, when the nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s composition is incorporated in the more flammable organic material an amount of 3 to 200% by weight, percentage based on the weight of the more flammable organic material, is utilized. When the aqueous nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s composition is applied on the more flammable organic material, in a sufficient amount, will produce a less flammable organic material. Usually an amount that will wet the surface of the flammable organic material is sufficient.
The aqueous or solid nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s composition is usually added on or incorporated in the flammable organic material or a fertilizer at ambient temperature and pressure but elevated temperatures and pressure may be utilized when necessary.
The nitrogen containing compound urea condensate salt of sulfur oxyacid may be produced by heating urea with the sulfur containing compounds in the sewer sludge and reduces the amount of sulfur oxides which is released into the air. When urea is heated it reacts with itself to produce condensates such as biuret, cyanuric acid and cyamelide. Ammonia is produced in the condensate reaction. The ammonium urea condensate salt of sulfur oxyacid may also be produced by reacting aqueous ammonium, urea and sulfur oxyacid found in the sewer sludge or by first reacting the ammonia with sulfur oxyacid to produce ammonium sulfur oxyacid then reacting it with urea or urea condensate or partially hydrolyzed urea condensate. These chemical reactions may take place at ambient or elevated temperature sufficient to melt the urea ranging from ambient to 180xc2x0 C.
One method to measure this flame retardant capability is an oxygen index test. By selecting the various combinations of the mixture of nitrogen containing compound urea or it""s compositions, which is then incorporate into a more flammable organic material, so that the average limiting oxygen index (LOI) can be raised 10 to 30 percent or more when compared to otherwise comparable samples without the flame retardant nitrogen containing compound urea composition. For example the LOI of three flexible polyurethane foams with the aqueous or solid nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s composition, were raised more than 30 percent to a LOI of 31.7, 30.3 and 30.7.
When the aqueous or solid nitrogen containing compound, urea and urea condensate reacted with sewer sludge and/or it""s composition was incorporated into rigid polyurethane foam and tested, with a propane torch with a 2xe2x80x3 flame held against the foam for one minute, the flame did not spread, the foam melted and/or a char was formed. The flame went out when the torch was removed. Various aqueous or solid nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s compositions were incorporated into liquid resins then cured into a solid in the form of a xe2x85x9xe2x80x3xc3x972xe2x80x3xc3x976xe2x80x3 sample, for example, flexible polyepoxy resins, rigid polyepoxy resins, polyester laminating and flexible resin, polystyrene resin, polymethyl methyl acrylate resin, polyvinyl acetate resin, polyurethane, polyisoprene, polyethylene, acrylonitrile, etc, then tested with a propane torch having a 2xe2x80x3 flame, and held against the sample for 30 seconds. The flame did not spread, and went out when the flame was removed. Various mixture of aqueous nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s aqueous compositions was add to aqueous emulsions and organic solutions of the above plastics, then dried to form a test sample, then tested as above with good results.
The flexible flame retardant polyurethane foams were tested and passed the Calif. TB 133 test which utilizes a 100 gms of wood in the form of a crib being burned on top of the flexible foam. If more than 60 gms of the foam burns away it fails this test.
Various natural products such as wood shingles, paper, cotton cloth, and cardboard were coated with various aqueous solutions containing 30% nitrogen containing compounds, urea and urea condensate reacted with sewer sludge and/or it""s compositions with or without adhesives. Then after the product had dried, they were tested by applying a 2xe2x80x3 flame from a propane torch against the products, and the flame did not spread whereas the non coated products caught on fire and burned.
The urea-urea condensate-sewer sludge composition will react with aldehydes to produce resins. Any suitable aldehyde may be used such as, but not limited to, formaldehyde, paraformaldehyde, acetoaldehyde, butyraldehyde, chloral, and other alkyl aldehydes, furfural, benzyl aldehyde, aromatic aldehydes and mixtures thereof. Aqueous formaldehyde is the preferred aldehyde. The aldehyde may be used in the amount of 25 to 200 parts by weight based on 50 to 100 parts by weight of the dry urea-urea condensate-sewer sludge composition. Any suitable basic or acid compound may be used as the catalyst in the reaction of the aldehyde with the urea-urea condensate-sewer sludge composition. A catalytic amount is utilized.